1. Field of the Invention
The subject invention relates to the fabrication and assembly of fuel injectors for gas turbine engines, and more particularly, to methods of fabricating and assembling fuel injectors using laser additive deposition techniques to locally enhance the mechanical properties of the fuel injector.
2. Background of the Related Art
Gas turbines engines used in military and commercial aircraft must satisfy high demands with respect to reliability, weight, performance, economic efficiency and durability. Among other things, the use of advanced manufacturing methods and materials selection play a decisive role in meeting these requirements.
Conventional methods for manufacturing gas turbine components include forging and investment casting. For example, the highly stressed components in the compressor region of a gas turbine are typically manufactured by forging, whereas the rotor and stator blades of the turbine are typically manufactured by investment casting.
Another known method of manufacturing, repairing or restoring blades used in gas turbine engines is laser consolidation. In this process, a laser is used to create a melt pool at a metal surface during which metal or ceramic powder is delivered by a nozzle into the melt pool to build up a three dimensional geometry. Examples of this process are disclosed in U.S. Pat. No. 6,269,540 to Islam et al. and U.S. Pat. No. 7,984,547 to Steinhardt.
Material selection for gas turbine components that are subjected to high mechanical loads, high vibration loads or high thermal loads is often based upon material limits being exceeded in localized regions of the component. Exceeding the material limits in a local region often causes the designer of the component to specify high-strength or otherwise exotic alloy materials for fabricating the entire component. The selection of an exotic material for the entire component tends to drive its cost up substantially.
It would be desirable to employ techniques used for laser consolidation of entire engine components to locally improve or otherwise tailor the mechanical properties of an engine component. In this regard, the subject invention provides for the use of laser cladding or additive manufacturing processes to locally improve the material properties of a gas turbine component, and more particularly, a fuel injector used within a gas turbine engine.
Thus, an improved material can be applied in areas where improved properties may be needed for strength, vibration or thermal management. By using an improved material in localized areas, a manufacturer can save cost and weight on the overall component design, while meeting the same certification or equal requirements provided for a standard component.